Certain current gas turbine fuel injection nozzles contain many small combustion air tubes, trapped between upstream and downstream plates and surrounded by a peripheral wall, forming a pressure vesicle. The tubes typically include a plurality of very small, low-angle, holes within the walls of the tubes for injecting fuel from the vesicle in to the interior of the tubes where the fuel and air are mixed before exiting the tubes and entering the combustion chamber. A fuel injection nozzle of this type is disclosed in commonly-owned U.S. Pat. No. 7,007,478 issued Mar. 7, 2006.
It will be appreciated that fuel injection nozzles as described above necessarily incorporate many braze joints at the tube/plate and plate/wall interfaces that are required to seal the hydrogen fuel, and that expensive EDM procedures are necessary to form the many small, low-angle fuel injection holes. In addition, intricate assembly methods are required to meet specified performance criteria. There remains a need therefore, for a process for manufacturing complex fuel nozzle geometries that reduces if not totally eliminates potentially leaky joints, and that also greatly reduces the need for post machining and/or EDM operations.